Wetsuit or No Wetsuit?

The water is warmer than normal this year for the Mackinaw Multisport Sprint Triathlon, hovering around 75 degrees, and I haven’t been in my wetsuit in several years. So, I felt like I was pouring myself into a full body compression suit for my morning swim…hmmm did I gain a few pounds? Ok, it’s only a sprint, a meager 800 yards. Do I wear the wetsuit or not wear the wetsuit? That is the question??

Wearing a wetsuit is known to increase swim performance, by increasing buoyancy and decreasing drag, much like a speedboat when it planes out on the water. In cold water it can prevent hypothermia and keep the swimmer more comfortable.

Let’s look at the difference a wetsuit makes at various distances and how it affects stroke mechanics. In an article reported in the Journal of Science and Medicine and Sport, Tomikawa et al. tested swimmers at 60% and 80% VO2 max, the average range of sub-maximal swim speeds during triathlon events. They found that:

1. The energy cost when swimming at 60% VO2 max and wearing a wetsuit was 14.4% lower than when not wearing one

2. The energy cost when swimming at 80% VO2 max and wearing a wetsuit was 7.5% lower than when not wearing one

3. When swimming at both 60% and 80% VO2 max, the swimmers stroke length did not change a great deal when wearing a wetsuit, but there was an increase in stroke rate (the arms were moving faster)

4. Swimming 1,500 meters at 80% VO2 max in a wetsuit would decrease swim time by 70 seconds compared to non-wetsuit swimming, based on the findings of this study

The researchers concluded that swimming without a wetsuit at 60% VO2 max increased energy usage, while energy usage was much lower when swimming with a wetsuit. When swimming at very slow speeds a swimmers body sinks further into the water causing more drag – hence the buoyancy of a wetsuit is a big help to slower swimmers in particular. When swimming at 80% VO2 max, the faster pace allowed the body to lift in the water, which reduced the benefits of the wetsuit.

In addition, the researchers noted that at even faster speeds (above 80% VO2 max) the buoyancy of the wetsuit made even less difference as the high velocities lifted the swimmers even further.

The other consideration in determining whether to don the wetsuit is the amount of time that will be sacrificed in transition removing the wetsuit. For fast swimmers, swimming shorter sprint distances, the wetsuit may not provide much of an advantage. For slower swimmers and also for longer events wetsuits definitely can swim reduce time.

What’s your preference and experience with wetsuits during triathlons or open water swim events?